Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is fully covered. The description adds the scoping detail that the chart is anchored to the birth moment and discloses a cost tier (50 credits), which is genuine extra context, but says nothing about response shape or computation limits.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two compact sentences that front-load the core action and the output definition, plus bracketed metadata for group and cost. Every element is doing work, though the group/cost tag is boilerplate rather than tool-specific substance.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values needn't be explained. However, for a 15-parameter tool with low schema coverage, the definition is too thin on parameter behavior and sibling differentiation to be fully complete, even if it is adequate on the core purpose.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is only 33% across 15 parameters, so the description carries a heavier burden to compensate. It adds no parameter meaning at all — nothing about required date/time/latitude/longitude, the sidereal option, house system, timezone handling, or the compact-mode fields/precision parameters.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (Calculate) and resource (local space chart), and defines the output precisely as azimuth and altitude of each planet from a geographic location at the birth moment. It does not, however, distinguish itself from the sibling astroway_geo_local_space_influence_zone or other geo tools, so an agent must infer the difference.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no when-to-use, when-not-to-use, or alternative guidance. With ~15 geo siblings (geo_acg, geo_relocation, geo_zenith, local_space_influence_zone), the description gives no hint about which geographic technique this is and when it is the right choice.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.